title: Structure and secretion of CofJ, a putative colonization factor of enterotoxigenic Escherichia coli.
abstract: Enterotoxigenic Escherichia coli (ETEC) colonize the human gut, causing severe cholera-like diarrhoea. ETEC utilize a diverse array of pili and fimbriae for host colonization, including the Type IVb pilus CFA/III. The CFA/III pilus machinery is encoded on the cof operon, which is similar in gene sequence and synteny to the tcp operon that encodes another Type IVb pilus, the Vibrio cholerae toxin co-regulated pilus (TCP). Both pilus operons possess a syntenic gene encoding a protein of unknown function. In V. cholerae, this protein, TcpF, is a critical colonization factor secreted by the TCP apparatus. Here we show that the corresponding ETEC protein, CofJ, is a soluble protein secreted via the CFA/III apparatus. We present a 2.6 Å resolution crystal structure of CofJ, revealing a large β-sandwich protein that bears no sequence or structural homology to TcpF. CofJ has a cluster of exposed hydrophobic side-chains at one end and structural homology to the pore-forming proteins perfringolysin O and α-haemolysin. CofJ binds to lipid vesicles and epithelial cells, suggesting a role in membrane attachment during ETEC colonization.
authors.affiliation: Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6.
authors.forename: Alex S W
authors.initials: AS
authors.lastname: Yuen
authors.forename: Subramaniapillai
authors.initials: S
authors.lastname: Kolappan
authors.forename: Dixon
authors.initials: D
authors.lastname: Ng
authors.forename: Lisa
authors.initials: L
authors.lastname: Craig
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D018938:Caco-2 Cells; D016384:Consensus Sequence; D018360:Crystallography, X-Ray; D054307:Enterotoxigenic Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010861:Fimbriae, Bacterial / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006367:HeLa Cells; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009876:Operon; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: C000589012:CofJ protein, E coli; D029968:Escherichia coli Proteins